I'd like to get a review/impression from someone that doesn't plan to create anything. I want to hear about the campaign and if its easy to play other peoples great creations like it is in Super Mario Maker 2.
The campaign is fun, though it is mostly easy platforming levels mixed with some point-and-click adventure segments. The characters, art design, and story are the real stars of the show - gameplay is not a whole lot to write home about. The campaign is very short but still satisfying.
Getting in and out of others' games is very fast and easy.
I think the biggest problem facing Dreams is that people will very quickly burn through all the good user-created content and then be left without much to do. Most of the games are very short and the only replayability comes from time or score challenges.
It takes a very long time for projects to be created, so people's appetitte for games to play will very quickly outstrip creators' ability to produce games.
I think Dreams is best suited to puzzle games. Most of the 3D action games feel like B-list platformers from the PS2 era.